Office Hours: Starting with fall semester 2011:Mon & Tues, 12:30-5:00; with reservation of sporadic lab preparation and service commitments as marked on the door of the office suite.

Teaching Assignments:

Class portfolio (2015)

Are you getting prepared for a class? For class itineraries and text books, contact me for Syllabus Factsheets.

BIOS 105

Plants and Society (non-science major, since spring 2015)

Spring

BIOS 110

Biology Principles I

Fall & Spring

BIOS 110L

Biology Principles I Laboratory

Fall & Spring

BIOS 224

General Botany

Fall & Spring

BIOS 224L

General Botany Laboratory

Fall & Spring

BIOS 293

Independent Studies

Upon call

BIOS 371+L

Systematic Botany (since 2011)

Spring

BIOS 470

Evolution, undergrad level

Spring

BIOS 670

Evolution, graduate level

Fall

BIOS 491

Independent research Projects

Fall

BIOS 495

Seminar: Phylogeny and evolution (since 2008)

Spring

Research Interests:

General and Past:My research interest is evolutionary biology of land plants, especially flowering plants (angiosperms) and non-flowering seed plants (gymnosperms). I am particularly interested in the evolution of development (EvoDevo) of the flower and floral organs, and other reproductive organs. Where did carpels and stamens come from? How did the ancestral organs look and how were they arranged throughout the plant, before we would recognize them as "flower"? Do we have fossil representations of these pre-angiosperms? Apart from the sporangia, what is the principal difference between a vegetative leaf and a floral organ? Is there any, at all?

Actual, and Student Research Opportunities:Synopsis:

1) Leaf development and evolution in Eusporangiate ferns: Ophioglossaceae and Psilotaceae are odd siblings.We re-examined the morphology of Psilotum. and found that the "green aerial frond" corresponds rather to fern aleaf than to a stem. With this, Psilotum indeed is "similar" to Ophioglossaceae in terms of organ identity of its parts. The differences that meks these taxa so oddly dissimilar are based on differences of their development: Heterochony and Homeotisis.

2) Fern embryology: tip-to-toe embryoIn the very early stage, also the embryo of regular ferns (model organism Ceratopteris) develops in a linear, bipolar manner. However, we have not yet identified hypostasis, root initiation in Ceratopteris, and we still have a long way to study the embryo of Pslotum or Ophioglossaceae.

3) Plant tissue culture: Louisiana Iris, day lilyThe purpose is to establish a successful protocol for plant tissue cultures derived from shoot apex meristems or parenchyma cells of select organism, such as Iris and Hemerocallis.

"Ferns" in general (Monilophytes) are the closest relatives of extant seed plants, and many know them as an archaic group of plants, associated with dinosaurs, etc. However, most ferns ("ferns" in the narrow sense) belong to a single group (or "clade") called Leptosporangiate Ferns, based on their very peculiar sporangium. This group radiated relatively recently, and is not really "archaic", but actualy modern; sadly, most truely archaic groups have died out. From all the "old style" ferns (eusporangiate ferns), only three groups have survived to today: Horsetails (Equisetaceae), Boat-ferns (Marrattiaceae), and the group of Ophioglossaceae and Psilotaceae.

This last group, Ophioglossaceae and Psilotaceae, is the biggest surprise of the last years' research. Psilotaceae, seemingly without leaves and or roots, was long time considered not a fern, but actually older than all other vascular land plants, older even than club-mosses (Lycophytes). Ophioglossaeae, however, with a peculiar stem growth, vascular system, and an elaborate axial, stem-like outgrowth bearing the sporanga, has been considered closer related to seed plants than normal ferns. Yet, molecular analysis revealed these two "opposite" families as two monophyletic sisters, and within the monilophytes. And: while a review of morphological data showed a great correspondance to molecular findings, it could not copy the molecular data for the Ophioglossaceae-Psilotaceae clade.

We re-examined the morphology of Psilotum. and found that the "green aerial frond" corresponds rather to fern aleaf than to a stem. With this, Psilotum indeed is "similar" to Ophioglossaceae in terms of organ identity of its parts. The differences that meks these taxa so oddly dissimilar are based on differences of their development: Heterochony and Homeosis.

Psilotum realy has no root - what happened to it? Is it initiated in the embryo? Actually, how do ferns in general initiate roots?

Seed plants have a strict bi-polarity in the pro-embryo: suspensor-embryo. The rood forms in below the suspensor from a defined cell layer (the "hypostatsis"), and grows clearly into the direction opposite to the shoot apex of the embryo. However, in fern embryos we knew, root and shoot apex emerge in one direction, opposite to the suspensor. That is, even the root development of regular ferns is not really understood.

The leptosporangiate fern Ceratopteris ("c-fern") is a model organism for fern genetics and development. We established a protocol for its gametophyte cultivation and were able to study the very early embryo development. We found, that in this very early stage, also the fern embryo develops in a linear, bipolar manner. However, we have not yet identified hypostasis, root initiation in Ceratopteris, and we still have a long way to study the embryo of Pslotum or Ophioglossaceae.

3) Plant tissue culture: Louisiana Iris, day lilyThe project is in collaboration between LSUS (Biological Sciences) and Plantation Point Nursery (Mooringsport LA). The organism are Louisiana iris and day lilies (Iris section Apogon and Hemerocallis). The primary intent is to transfer rhizomatous tissue (parenchyma and shoot apex meristems) to a solid growth gel containing cell dedifferentiating growth factors, resulting in a plant tissue callus. A second approach may use seeds as tissue start.

The bulk of storage and maintenance operation would be in Mooringsport and not burden LSUS facilities. It provides the opportunity to train students on a standard method used in agriculture, horticulture, and plant biology. The outlook of this project is to apply the findings onto the fern research project mentioned above.